Project Summary/Abstract Cochlear implants are commonly used in young children to treat deafness. This electronic device receives incoming sounds and electrically stimulates the auditory nerve, thereby bypassing the malfunctioning inner ear. Achieving optimal results with a cochlear implant requires individualized programming of the device so that it appropriately stimulates the central nervous system combined with comprehensive speech and language therapy dedicated towards auditory habilitation. While speech and language outcomes after pediatric cochlear implantation can be exceptional, there are individual failures. These failures may be due to inadequate programming of the device. Programming a cochlear implant inappropriately can be disastrous for a deaf child because there is only a short time window to acquire optimal speech and language during their first few years of life. Thus, there is a clinical need for additional objective measures of whether or not a cochlear implant is providing appropriate auditory stimulation to a deaf child. This research will translate the basic science technique of near-infrared spectroscopy (NIRS) to optically image functional brain activity within the receptive language cortex (the superior temporal gyrus) in pediatric cochlear implant patients. NIRS is a non-invasive technique that measures cerebral hemodynamic changes associated with neuronal activity. The sensitivity and specificity of NIRS to assess cochlear implant function will be determined using behavioral audiometry as a gold standard. This will be performed in reliable children who have used a cochlear implant for >2 years and in children who are undergoing initial activation of their cochlear implant. We will test the ability to NIRS to measure responses to broad-band speech stimuli. Successful completion of these aims will describe the feasibility and reliability of using NIRS as a supplemental measure of auditory perception in pediatric cochlear implant patients. This interdisciplinary translational research will include key personnel with expertise in signal processing, the use of NIRS in children, fMRI neuroimaging, cochlear implantation, and biostatistics. The long term goal of this research is to develop NIRS into a clinical tool that can supplement current techniques used by cochlear implant teams to program a child[unreadable]s cochlear implant. Ultimately, this should improve pediatric cochlear implant outcomes.